High-alumina Brick Research Articles

Service of chamotte and high-alumina brick in blast-furnace stack

Destruction of refractory brickwork in the top of the blast furnace stacks at the Magnitogorsk Metal Works is restricted on account of the relatively low temperatures of the medium and occurs mainly through the abrasive effect of the blast charge and the gas stream. The absence of hardened slag on the brickwork in the middle of the stack and the high temperature of the medium have an effect on the extensive wear and tear of the lining subjected to the abrasive gas stream. The wear becomes worse on account of the deposition of zinc, alkalies and carbon soot on the brickwork. Reasons for cracking and striation of refractory brick should be studied. In the bottom area of the stack the high-alumina brick showed the same strength as other types of lining materials. However, since the properties of this brick after service (density, strength, etc.) were practically the same, further tests should be carried out in the middle section of blast-furnace stacks.

Increasing resistance of open-hearth furnace checkers

The use of high-alumina brick in the top rows not only lengthens the life of the checkers in on open-hearth furnace, but improves the output of the furnace itself.

Production of high-alumina blocks for blast-furnace bottoms

A hydraulic 1500-ton press is now used to produce high-alumina blocks 400×200×120 mm in size and 550×200× ×150 mm, in accordance with the specification for high-alumina bricks for large-size blast furnace bottoms. A technological system has been devised for manufacturing the blocks.

High-alumina light weight brick and its use

High-alumina light weight brick and its use

High-alumina light weight brick and its use

A production technique has been worked out for the manufacture of high-alumina lightweight brick by the combustible additive method with semi-dry pressing of the mixtures. These parts can be used for the working layer of the lining at temperatures up to 1550°.

Production of a test batch of high-alumina brick from Latnaya clay and commercial alumina

Production of a test batch of high-alumina brick from Latnaya clay and commercial alumina

The refractory brick and mortar for aluminium holding furnace and its baking method

This is to report on the study on the suitability of refractries for the lining of aluminium holding furnance. In this investigation, it was found that high alumina brick presented the best result. It was decided, as the result, the high alumina brick with the following properties is to be used for the actual operation.1. Chemical analysisSiO2 6.5%Al2O3 90.7%Fe2O3 1.9%TiO2 0.9%2. Reacted with molten alminium, and the content of SiO2 is slightly reduced.3. Slightly attacked by molten fluoride.4. The spalling test by rapid heating and cooling alternately more than 15 times.5. Correlative abrasion with alminium ingot 0.02g/100rev.6. Compressive strength 734kg/cm27. Apparent porosity 24.0%8. Water adsorption 8.4%9. Modulus of elasticity 5932kg/mm210. Apparent density 3.811. Thermal expansion (showed in Fig. 10)12. Water diffusion coefficient in the natural drying condition 0.0001m2/day13. Water diffusion coefficient in the forced drying condition 0.0024m2/dayIn case of lining furnace with this high alumina brick, the binder between the bricks should be half melted at 850°C, which is the finishing temperature of the furnace baking, and should be solidified at 750°C, the operating temperature of the furnace. Considering with this factor, special mortar of the following composition is to be used:Fused alumina in powder state 71.5%As best fiver 1.5%Sodium silico-fluoride 12.0%Soluble glass 15.0%Water operating amountThe furnace is reached to the operating condition without any trouble, when the above mentioned brick and mortar are used and the temperature of the furnace is raised in accordance with the temperature raising program. In this case the water content in bricks and the elongation of bricks took place during heating should be taken into consideration.

Application of Sonic Moduli of Elasticity and Rigidity to Testing of Heavy Refractories

The application of A.S.T.M. C 215‐51 T (Tentative Method of Test for Fundamental Transverse Frequency of Concrete Specimens for Calculating Young's Modulus of Elasticity) to the nondestructive testing of 1‐ by 1‐ by 7‐in. laboratory fire‐clay specimens and standard 9‐in. fire‐clay and high‐alumina refractory brick is reviewed. Both room‐temperature measurements and hot sonic modulus of elasticity measurements to 1700°F. are analyzed. Sonic moduli of elasticity and rigidity are compared with modulus of rupture by a theory of measurements and statistical analysis. The limits of uncertainty of the average of modulus of rupture are shown to be a function of the degree of verification whereas in the case of both sonic moduli they are not. Limits of uncertainty of the average of sonic moduli data are usually of the same order as errors calculated from the precision of measurements. In the case of modulus of rupture of well‐vitrified clays, the uncertainty of the average is much greater than calculated error limits. Sonic moduli differentiate statistically between two samples of 60% alumina brick whereas modulus of rupture does not. If Poisson's ratio is assumed to be zero rather than the conventional one‐sixth, ratios of sonic modulus of elasticity to rigidity are shown to approximate the theoretical ratio more closely. Effects of nonuniform density to displace normal nodes are illustrated. Hot sonic modulus of elasticity is shown to reflect changes due to crystallographic inversions, deterioration of chemical bond in unfired brick, and development of sintered bond in unfired brick.

ELASTIC BEHAVIOR AND CREEP OF REFRACTORY BRICK UNDER TENSILE AND COMPRESSIVE LOADS*

AbstractSpecimens cut from 9‐in, brick of nine brands of firebrick, including two high‐alumina, four fire‐clay, two siliceous fire‐clay, and one silica, were subjected to tensile and compressive creep tests at eleven temperatures from 25° to 950°C., inclusive. The duration of each test was approximately 240 days. Small length changes, independent of stress direction (that is, compressive or tensile), occurred at the lower temperatures. The lowest temperatures at which creep was significant were (a) high‐alumina brick, 700° to 850°C.; (b) fire‐clay brick, 600° to 700°C.; and (c) siliceous and silica brick, 950°C. Creep results under compressive stress could not be correlated with results under tensile stress. Specimens of different brands, at 950° C. showed greatly different capacities to carry load. Repeated heatings caused growth of silica brick of approximately 0.27%. Moduli of elasticity at room temperature were determined before and after the various heat‐treatments and resultant changes were recorded. The changes in moduli were 15% or greater for silica and siliceous brick and 4% or less for the fire‐clay brick. The moduli of elasticity at room temperature were approximately 2.7–4.3 × 106 for high‐alumina brick, 0.6–1.9 × 106 for fire‐clay brick, 0.3–1.7 × 106 for siliceous fire‐clay brick, and 0.4 × 106 for silica brick.

CHECKER BRICK FOR RESISTING ALKALINE SLAGS1

ABSTRACTChecker brick of varying composition were tested by placing them in the regenerators of two glass tank furnaces. The operation of one furnace was representative of those making the usual grade of bottle glass while the other was operated at a considerably higher temperature and with a more corrosive dust.The amount of corrosion of the checker brick varied directly with the silica content of the brick. Those highest in alumina gave excellent service in the regenerator operating at the lower temperature. In the other regenerator, however, the. dust adhered to the high alumina brick and tended to clog the regenerator while it apparently fluxed and drained off of those higher in silica, leaving free passage for the gases.The brick were tested in the laboratory by making into cones with various percentages of the corrosive dust and determining the fusion point of the cones. The results agree closely with those obtained from the service tests.Detailed results including partial analyses of the brick and flue dust are given.